Analysis of cooling performance using evaporation enthalpy of product water for a lightweight aviation fuel cell system

Abstract

In air mobility vehicles, weight reduction has a significant impact on extending flight duration and increasing payload. However, as the power demand of the fuel cell increases, a large cooling capacity is required, which increases the weight of the entire cooling system including the coolant. Therefore, this study investigates ways to reduce the volume and weight of the thermal management system of the 20kW high-power fuel cell system. Instead of removing the external humidification system for both the anode and cathode, the effect of humidification is evaluated using the product water discharged from the stack. In addition, a method to maximize the cooling effect of the radiator by using the latent heat of evaporation of generated water is proposed. Also, system designs with more effective heat removal capability are derived by dividing the case into two according to the system arrangement. Before the analysis, a stack model capable of simulating the complex physics of the fuel cell was developed using Aspen Custom Modeler®. As a result, it was confirmed that the minimum specification (required overall heat transfer coefficient, UA) of the radiator can be reduced by using each product water discharged from the stack.